The invention relates to actuator cylinders, more particularly for operation by compressed air, with a cylinder barrel shut off at one end, a piston able to run backwards and forwards axially in the barrel and mounted on a piston rod protruding from the barrel through a first cylinder end plate, and a stop for limiting the maximum amount of extension of the piston rod from the barrel by cooperation with the moving plunger as formed by the piston and the piston rod.
In known arrangements of this type as so far proposed the piston rod has a part joined to it that is placed outside one end plate to serve as an abutment for cooperation with a stop placed at a distance from the end plate and which may be axially adjusted to set the maximum extension of the piston rod from the cylinder barrel. Such piston and cylinder units frequently have to be used for applications in which space is at a premium, as for example in a machine tool processing some form of workpiece, so that the presence of such an external system of abutments increasing the space requirement of the piston and cylinder unit is likely to be more than a marginal disadvantage. Furthermore, the abutment system may be fouled by dirt and because the one abutment acts eccentrically, there may be appreciable signs of wear after running for only a short time. Moreover, the abutment system, that also has to keep its set position, puts up the costs of manufacturing the piston and cylinder unit.